Caló
Caló or Spanish Romani is a language spoken by the Gitanos or Zincarli living in Spain and elsewhere: Caló blends native Romany vocabulary with Spanish grammar(1). There is a growing awareness and appreciation for Caló: "...until the recent work by Luisa Rojo, in the Universidad Autonoma de Madrid, not even the linguistics community recognized the significance and problems of Caló and its world.(2)" Its world includes songs, poetry, and Flamenco(3). According to the Ethnologue, Caló is related to another nomadic group's language, Quinqui.
Reference
1. Ethnologue
2. The Responsibility of Linguist and the Basque Case
See also
Germanía This is another Spanish jargon.